i would go with the legend of zelda just because it was one of the first video games i ever played and may as a second game i would say super mario galaxy
my worst experience in kh1 was when i was looking for all the materials for the ultima keyblade it sucked ass i spent over a week trying to find everything it was a **** storm
my worst experience with kh2 was when i was fighting xemnas i spent an hour on him i got him to low health and then he would kill me!!!!!!!!!
well if my memory serves me correct in the game it was said that the cornerstone of light had always been on cornerstone hill and if thats the case then how is it that cornerstone hill got turned into disney castle i mean why couldn't they build disney castle somewhere else